Apparatus for making hydrochloric acid.



H. HOWARD.

APPARATUS FOR MAKING HYDROCHLORIC ACID.

APPLICATION FILED IuNEZ. 1914..

L Mgm Patented July 13, 1915.

2 SHEETS-SHEET l.

H. HOWARD.

APPARATUS FOR MAKING HYDROCHLORIC ACID.

. APPLICATION FILED IuIIE26, 1914.

hmwt, PIIIenIed Jul-y 13, 1915. l

2 SHEETS-SHEET 2.

IIIIIIIII P A A gII=III WL. /VZEMA ,JWM l l C. Umm ,I @www f @WM found materially to vHENRY HOWARM, 0F BROOKLINE, `MSSJGHUSIIEl'lll'llS.

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amener,

Specication of Letters Patent.

Patente duly f3, fhfh,

Application tiled JT une 2d, fait. herial No. 847,'2299.A

To all whom tt may concern:

Be it known that ll, HENRY HOWARD, a citizen of the United States, residing at Brookline, in the county of Norfolk and State of Massachusetts, have invented certain new and useful lm rovements Apparatus for Making Hy ochloric Acld, of which the following is a specication.

'lhis invention relates to apparatus for making hydrochloric acid in mechanical salt-cake furnaces, the object of the invention being to provide an apparatus by means of which the salt (sodium chlorid) and sulfurie acid, in the form of partially` decomposed reactionmixture or paste,-may be fed continuously and at a uniform rate to the mechanical furnace. 1

ln the manufacture of hydrochloric acid by the decomposition of salt^by sulfuric acid in mechanical salt-cake furnaces, it is customary to feed the salt and sulfuric acid separately to the furnace, the evolved gaseous hydrochloric acid being absorbed by water in a suitable absorption train. lf have found that decided economies in the operation are secured by commingling the salt and acid in accurately predetermined proportions before their introduction into the furnace, and continuously feeding the mixture, in the form of a partially decomposed paste, to a suitable which it is stirred and calcinedto complete the reaction., By proceeding in this way, a nearly instantaneous reaction is/obtained in the furnace, particularly when the salt is in the form of ne powder, and by feeding the paste continuously and uniformly to the furnace at a rate commensurate 'with its capacity, therel is obtained a copious and uniform evolution of hydrochloric-acid gas under conditions highly favorable for economic operation. This procedure has been the furnace, as compared with the results obtainable under the prior practice of separately feeding the salt and acid, and also to render it entirely feasible to carry out the whole operation on a single hearth of l7.,

the Mannheim type. llt is necessary, however, under the present procedure to provide not only for the absorption of the gas evolved by the reaction in the furnace, but also for the absorption of the lesser quanymixture be 'mingled before their mechanical furnace in increase thecapacity of `through the bottomoutlet d into tities of gas evolved from the reaction minture or paste before its admission to the furnace. I

llt is essential to the successful operation that the salt and acid should be delivered-to the furnace in the forni of a mixture of uniform composition, the components of the y' g in absolutely controlled relative quantities. Under these conditions, and ina furnace of the type described, the mixture is fed-to a hearth which carries a large v quantity of highly heated and nearly dry result-that the fursulfate of soda, with the nace charge as a whole does not at assume a liquid or past reaction may be carrie single step or sta e. rlhis uniformity in the composition o the mixture is secured either by coordinating the feed of the salt any time to completion in a and acid to a suitable-mixing device in such manner that these feeds vary proportionately in so faras they vary at all, or by introducing the salt and acid in proper weighed proportions into a suitable mixing devlce, in which they are thoroughly4 comintroduction into the furnace.

A preferred form of apparatus embodying the. invention is illustrated in the accompanying drawings, wherein- Figure l tus, partlyy in section; Fig. Q-is a transverse vertical section of the acid feeding device; and Fig. 3 is an elevation, partly in section, of a modied form of apparatus.

vlin said drawings, l represents, diagrammatically, a single-hearth mechanical saltcake furnace ofthe Mannheim type, which in practice is provided with the usual stirring means and is constructed for continuous operation. p

2 is the saltpan, provided with a rotary feeding mechanism 3, and discharging a conveyer 5 which leads directly to the'furnace l.' The gases evolved from the furnace pass throu h the standard@ to a suitable. absorption train means of a worm-gear' 8o in the required proportion to the salt is fed 1n successive equal portionsto .the conveyor 5 at a point between the salt pan and the condition, and the' 'lhe conveyer 51s shownas operated hoy-jm@ lln the apparatus illustrated, sulfuric acid i 1s an elevation of the apparaf veyer 5. By operating/,t

'- scribed,

, to the capacity of the conveyer, it is .to prevent and the cylinder 9, interconnected through the belt 12, are always driven in synchronism. The cylinder 9 carries at one end a dipping-tube 13 which revolves in a vertical plane in the direction indicated by the arrow in Fig. 2. This tube is closed at its outer end. and is provided on its advancing side with an aperture 14, which is preferably angular, and which extends to, but not beyond, the central line of the tube. This tube discharges into the cylinder 9 as it reaches the horizontal position in its movement of rotation, and delivers equal quantities of acid at each revolution, irrespective of the depth of acid in the tank 15, provided only enough acid be present to ll the cup end of the tube in its lowermost position. The acid is discharged at each revolution into a small receiving vessel 16, whence it is carried by ipe 17 to the consynchronism with the mechanical conveyer for the salt, and pro erly proportioning the capacity rate o revolution of the tube racticable to deliver the proper mixture o salt and acid to the furnace under all conditions and at a controllable rate.

The acidfeeding device as above deis claimed in my copending applicatin Serial No. 848,457 filed July 1, 1914. Instead of this particular form of acid feed, I-may employ other devices capable of accomplishing'a like result.

In the operation of this apparatus, the pan 2'serves as a storage receptacle for the salt andthe convyer mixes the salt and acid to a substanti ly uniform paste, while the body of iine salt in the pan and in the rear of the conveyer acts as an effective seal any escape of the gaseous hydrochloric acid. The gasset free by the partial decomposition occurring in the conveyer, passes into the furnace with the partially decomposed mixture, and thence, together with the reaction gases from the furnace, to the absorption tram 7.

The invention is not restricted to the employment of the particular apparatus illustrated. For-example, if desired, I may supply salt and acid in weighedpproportionate quantities ,directly to the pan 2 which in such case, should be constructed of a material resistant to hydrochloric acid, properly covered, and piped to the absorption system. Or, if desired, I may introduce into the pan a mixture of sodium chlorid and acid sodium sulfate, the latter in smaller proportion than'is required for the decome dipping-tube in position of the sodium chlorid, the required amount of sulfuric acid to com lete the decomposition ofthe vsalt being elther fed tothe mixture on its way to the furnace or introduced in weighed portions into the mixing pan, as above described.

A closed-pan apparatus of the type above referred to is illustrated in Fig. 3. In this apparatus, the mechanical furnace and the absorption train are provided, as in Fig. 1. The mixing-pan 2 is provided with a cover 1 8, and a gas connection 19 leads directly to the absorption train 7. The salt, or mixture of salt with acid sodium sulfate, is supplied to this pan in successive weighed quantities through a hopper 20, having a suitable closure. The acid, in the required weighed amounts, is fed in through a sealed inlet pipe 21 from the weighing-vessel 22. The salt and acid are thoroughly mixed in the pan and also in the conveyer 5 without external heating, and are continuously transferred by the conveyer 5 `to the furnace 1.

The process herein described is claimed in my copending application Serial No. 847,500, filed June 26; 1914.

I claim 1. In apparatusfor making hydrochloric acid, an absorption system for hydrochloric acid gas, a sealed mixing device communicating therewith, means for supplying salt and sulfuric acid to said mixing device in the necessary predetermined proportions, a suitable single-stage. mechanical salt-cake furnace also connected to the absor tion system, and means for continuously elivermg the mixture to said furnace.

2. In apparatus for making hydrochloric acid, an absorption system for hydrochloricacid gas, a sealed mixin device communicating therewith," cordinated means for supplying salt and sulfuric acid to said mixing device in the necessary predetermined proportions, a suitable mechanical salt-cake furnace also connected to the abso tion system, and means for continuously elivering the mixture to said furnace.

3. In apparatus for making hydrochloric acid, an absorption system for hydrochloric acid gas, a mixing device communicatin therewith and ada ted to be sealed by a he of salt, cordinate means for supplymg salt and sulfuric acid to said mixing device in the necessary predetermined proportions, a suitable mechanical salt-cake furnace also connected to the absorption system, and means for continuously elivering the mixture to said furnace.

4. In apparatus for making hydrochloric acid, an absorption system for hydrochloric acid gas, a storage vessel for sa t provided with feeding means, a mechanical salt-cake furnace, a salt-conveyer leading from said y storage vessel to said furnace and constructted to be sealed by the salt in said vessel,

meneer m means for introducing predetermined quantities of sulfuric acid into said sealedconveyer, means for cordinating the supply of In testimon whereof ax my signature in presence o two witnesses.

salt and acid to maintain the necessary pre- HENRY HOWARD' determined proportions, and a conduit for Witnesses: hydrochloric acid gas extending between THos. J. SHANNON,

said furnace and absorption system. M. V. BRmN. 

